/
log.go
188 lines (166 loc) · 3.54 KB
/
log.go
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package log
import (
"io"
"os"
"path"
"sort"
"strconv"
"strings"
"sync"
api "github.com/cipherzzz/commitlog/api/v1"
)
type Log struct {
mu sync.RWMutex
Dir string
Config Config
activeSegment *segment
segments []*segment
}
func NewLog(dir string, c Config) (*Log, error) {
if c.Segment.MaxStoreBytes == 0 {
c.Segment.MaxStoreBytes = 1024
}
if c.Segment.MaxIndexBytes == 0 {
c.Segment.MaxIndexBytes = 1024
}
l := &Log{
Dir: dir,
Config: c,
}
return l, l.setup()
}
func (l *Log) setup() error {
files, err := os.ReadDir(l.Dir)
if err != nil {
return err
}
var baseOffsets []uint64
for _, file := range files {
offStr := strings.TrimSuffix(file.Name(), path.Ext(file.Name()))
off, _ := strconv.ParseUint(offStr, 10, 0)
baseOffsets = append(baseOffsets, off)
}
sort.Slice(baseOffsets, func(i, j int) bool {
return baseOffsets[i] < baseOffsets[j]
})
for i := 0; i < len(baseOffsets); i++ {
if err := l.newSegment(baseOffsets[i]); err != nil {
return err
}
// Skip the next index because we know it's the index file.
// recall that we save an index file and a store file with the same base offset and different suffixes
i++
}
if l.segments == nil {
if err := l.newSegment(l.Config.Segment.InitialOffset); err != nil {
return err
}
}
return nil
}
func (l *Log) Append(record *api.Record) (uint64, error) {
l.mu.Lock()
defer l.mu.Unlock()
off, err := l.activeSegment.Append(record)
if err != nil {
return 0, err
}
if l.activeSegment.IsMaxed() {
err = l.newSegment(off + 1)
}
return off, err
}
func (l *Log) Read(off uint64) (*api.Record, error) {
l.mu.RLock()
defer l.mu.RUnlock()
var s *segment
for _, segment := range l.segments {
if segment.baseOffset <= off && off < l.activeSegment.nextOffset {
s = segment
break
}
}
if s == nil || s.nextOffset <= off {
return nil, api.ErrOffsetOutOfRange{Offset: off}
}
return s.Read(off)
}
func (l *Log) Close() error {
l.mu.Lock()
defer l.mu.Unlock()
for _, segment := range l.segments {
if err := segment.Close(); err != nil {
return err
}
}
return nil
}
func (l *Log) Remove() error {
if err := l.Close(); err != nil {
return err
}
return os.RemoveAll(l.Dir)
}
func (l *Log) Reset() error {
if err := l.Remove(); err != nil {
return err
}
return l.setup()
}
func (l *Log) LowestOffset() (uint64, error) {
l.mu.RLock()
defer l.mu.RUnlock()
return l.segments[0].baseOffset, nil
}
func (l *Log) HighestOffset() (uint64, error) {
l.mu.RLock()
defer l.mu.RUnlock()
off := l.segments[len(l.segments)-1].nextOffset
if off == 0 {
return 0, nil
}
return off - 1, nil
}
func (l *Log) Truncate(lowest uint64) error {
l.mu.Lock()
defer l.mu.Unlock()
var segments []*segment
for _, segment := range l.segments {
if segment.nextOffset <= lowest+1 {
if err := segment.Remove(); err != nil {
return err
}
continue
}
segments = append(segments, segment)
}
l.segments = segments
return nil
}
func (l *Log) Reader() io.Reader {
l.mu.RLock()
defer l.mu.Unlock()
readers := make([]io.Reader, len(l.segments))
for i, segment := range l.segments {
readers[i] = &originReader{segment.store, 0}
}
return io.MultiReader(readers...)
}
type originReader struct {
*store
off int64
}
func (o *originReader) Read(p []byte) (n int, err error) {
n, err = o.ReadAt(p, o.off)
o.off += int64(n)
return n, err
}
func (l *Log) newSegment(off uint64) error {
s, err := newSegment(l.Dir, off, l.Config)
if err != nil {
return err
}
l.segments = append(l.segments, s)
l.activeSegment = s
return nil
}